| Message ID | 20201129084516.1456099-1-christophe.jaillet@wanadoo.fr (mailing list archive) |
|---|---|
| State | Rejected |
| Headers | show |
| Series | Input: Fix a ref counting issue | expand |
Hi Christophe, On Sun, Nov 29, 2020 at 09:45:16AM +0100, Christophe JAILLET wrote: > In case of a managed resource, 'devm_input_device_release()' already has a > 'input_put_device(dev)' call. > > Avoid a double reference decrement by explicitly calling > 'input_put_device()' only on non-managed input device. This patch is incorrect, as devres_destroy() that is used in input_free_device(), unlike devres_releasde(), does not actually call the "release" function. It simply destroys the devres object, but does not clear associated resources. > > Fixes: 2be975c6d920 ("Input: introduce managed input devices (add devres support)") > Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> > --- > This patch is completely speculative and compile tested only. > --- > drivers/input/input.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/input/input.c b/drivers/input/input.c > index 3cfd2c18eebd..c09c9f020667 100644 > --- a/drivers/input/input.c > +++ b/drivers/input/input.c > @@ -1920,7 +1920,8 @@ void input_free_device(struct input_dev *dev) > devm_input_device_release, > devm_input_device_match, > dev)); > - input_put_device(dev); > + else > + input_put_device(dev); > } > } > EXPORT_SYMBOL(input_free_device); > -- > 2.27.0 > Thanks.
Le 29/11/2020 à 20:49, Dmitry Torokhov a écrit : > Hi Christophe, > > On Sun, Nov 29, 2020 at 09:45:16AM +0100, Christophe JAILLET wrote: >> In case of a managed resource, 'devm_input_device_release()' already has a >> 'input_put_device(dev)' call. >> >> Avoid a double reference decrement by explicitly calling >> 'input_put_device()' only on non-managed input device. > This patch is incorrect, as devres_destroy() that is used in > input_free_device(), unlike devres_releasde(), does not actually call > the "release" function. It simply destroys the devres object, but does > not clear associated resources. Crystal clear. Thanks for the explanation and sorry for the noise. CJ >> Fixes: 2be975c6d920 ("Input: introduce managed input devices (add devres support)") >> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> >> --- >> This patch is completely speculative and compile tested only. >> --- >> drivers/input/input.c | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/input/input.c b/drivers/input/input.c >> index 3cfd2c18eebd..c09c9f020667 100644 >> --- a/drivers/input/input.c >> +++ b/drivers/input/input.c >> @@ -1920,7 +1920,8 @@ void input_free_device(struct input_dev *dev) >> devm_input_device_release, >> devm_input_device_match, >> dev)); >> - input_put_device(dev); >> + else >> + input_put_device(dev); >> } >> } >> EXPORT_SYMBOL(input_free_device); >> -- >> 2.27.0 >> > Thanks. >
diff --git a/drivers/input/input.c b/drivers/input/input.c index 3cfd2c18eebd..c09c9f020667 100644 --- a/drivers/input/input.c +++ b/drivers/input/input.c @@ -1920,7 +1920,8 @@ void input_free_device(struct input_dev *dev) devm_input_device_release, devm_input_device_match, dev)); - input_put_device(dev); + else + input_put_device(dev); } } EXPORT_SYMBOL(input_free_device);
In case of a managed resource, 'devm_input_device_release()' already has a 'input_put_device(dev)' call. Avoid a double reference decrement by explicitly calling 'input_put_device()' only on non-managed input device. Fixes: 2be975c6d920 ("Input: introduce managed input devices (add devres support)") Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> --- This patch is completely speculative and compile tested only. --- drivers/input/input.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)